OBJECTIVE: In a randomized multi-center trial, we demonstrated that inhaled nitric oxide begun between 7 and 21 days and given for 24 days significantly increased survival without bronchopulmonary dysplasia (BPD) in ventilated premature infants weighing <1250 g. Because some preventative BPD treatments are associated with neurodevelopmental impairment, we designed a follow-up study to assess the safety of nitric oxide.STUDY DESIGN: Our hypothesis was that inhaled nitric oxide would not increase neurodevelopmental impairment compared with placebo. We prospectively evaluated neurodevelopmental and growth outcomes at 24 months postmenstrual age in 477 of 535 surviving infants (89%) enrolled in the trial.RESULTS: In the treated group, 109 of 243 children (45%) had neurodevelopmental impairment (moderate or severe cerebral palsy, bilateral blindness, bilateral hearing loss, or score <70 on the Bayley Scales II), compared with 114 of 234 (49%) in the placebo group (relative risk, 0.92; 95% CI, 0.75-1.12; P = .39). No differences on any subcomponent of neurodevelopmental impairment or growth variables were found between inhaled nitric oxide or placebo.CONCLUSIONS: Inhaled nitric oxide improved survival free of BPD, with no adverse neurodevelopmental effects at 2 years of age.